1. Field of the Invention
The invention relates to a drive unit for a nutsche process filter. More specifically, the invention relates to drive units that make such filters more compact and subject to less wear.
2. Background
Nutsche filters are used to react, wash, dry, separate, filter and otherwise process liquid solutions. Such processing may cause the formation of cakes. The Nutsche filters are capable of stirring, shaving, discharging or smoothing ("processing") the cakes.
Some Nutsche filters operate by lowering a turning impeller into the filter vessel containing the liquid solution. In prior art systems, the impeller shaft is typically driven by a reversible motor where rotational motion is translated from the motor through a gear arrangement to the shaft.
In operation, the impeller is lowered into and lifted out of the liquid solution by hydraulic arms. Typically, the arms are connected to the top of the shaft by a yoke. The hydraulic arms, motor and gear arrangement comprise the nutsche filter drive system. The drive system is capable of operating the nutsche filter. However, there are some drawbacks.
Existing nutsche filter drives require that either the motor and gear drive or drive shaft be raised from their lowest position above the filter vessel in order to raise the impeller shaft and impellers which are contained within the vessel. The present invention eliminates having to raise the drive shaft, gear drive or motor from their fixed positions above the filter. Thus, the drive components become stationary items.
Another drawback involves the height of the nutsche filter. Many nutsche filters stand over 15 feet high. The drive unit is disposed on top of the vessel and space must be allowed for travel of the motor and speed reducer or shaft when raising the impeller. The vertical space required for operation may make it difficult, if not impossible, to operate in many buildings. Furthermore, the shaft may be exposed to dirt and corrosion when lifting the impeller.
The problems identified with the present nutsche filter drive system are meant to be illustrative and are not exhaustive. Rather, this discussion is intended to show potential areas of improvement.